Spring drive apparatus



Dec. 26, 1961 R. C. LORD SPRING DRIVE APPARATUS Filed Nov. 1, 1957 k LOAD I G 2 T16 3 INVENTOR.

RICHARD C. LORD 32 TOR Y United States."

Fice

3,914,555 SPRING DRHVE APPARATUS Richard (3. Lord, Endicott, N.Y,, assignor to International Business Machines Corporation, New Yorlr, N.Y., a corporation of New York Filed Nov. 1, 1957. Ser. No. 693,860 3 (Ilaims. (Cl. 185-43) This invention relates to spring drive apparatus, and particularly to an arrangement whereby an output shaft has a relatively constant torque available for intermittent use.

There are a number of different types of spring drive apparatus available for supplying a shaft output on either a continuous or intermittent basis. in certain types of clock drives, for example, a winding mechanism is periodically operated to wind a spring so that torque is available at an output shaft. A disadvantage of this arrangement is that the torque available to do work is nonlinear in nature from the time the spring is completely wound until the time it is ready to be rewound. In contrast to this type of arrangement, the present invention utilizes a continuously running input shaft which is intermittently connected to wind a spring only when it is neces sary to do so in order to provide a substantially constant torque available on an output shaft which may be intermittently operable at and for variable intervals of time.

A primary object of the present invention is to furnish a new and improved spring drive or spring motor arrangement for providing a substantially constant torque available at an output shaft.

Another object of this invention is to provide a new and improved arrangement for coupling a continuously running input shaft to wind a spring only when there is an indication by the spring that it needs to be wound in order to provide a substantially constant torque to an output shaft.

A still further object of this invention is to provide a new and improved arrangement for coupling a continuously running input shaft by way of an energy storage device to an output shaft which may be operating intermittently at varying intervals.

Other objects of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of examples, the principle of the invention and the best mode, which has been contemplated, of applying that principle.

In the drawings:

FIG. 1 shows a front elevation view of the invention with the continuously running portion of the invention being engaged to wind the storage spring;

FIG. 2 shows a front elevation View of the invention similar to FIG. 1 except that in FIG. 2 the continuously running portion of the invention is disengaged from the spring winding means; and

PEG. 3 is a sectional view taken on lines 3-3 of FIG. 1.

Briefly, the present invention comprises a continuously running hollow input shaft having a flange thereon, said flange having a detent therein. A disc is journalled on said input shaft adjacent said flange. There is furnished a pawl which is pivotally connected intermediate its ends to the disc, one end of said pawl having a tooth formed thereon which is adapted to engage the detent in the flange. The output shaft is journalled in said hollow shaft and has one end which projects beyond said flange so that a spiral spring may be connected between said one end of the shaft and to the other end of said pawl. The arrangement is such that when the spiral spring is unwound to a certain degree, the end of the spring connected to the pawl urges the pawl to pivot so that the tooth thereof engages the detent on the continuously running flange. This causes the spring to begin to be wound. When the spring is substantially fully wound, the end of the spring connected to the pawl urges the pawl to pivot so that the tooth is disengaged from the detent. Thus, the spring is available for supply torque to the output shaft, there being suit able means furnished to prevent the spring from unwinding except by way of the output shaft.

For a more detailed description, reference is made to the drawings wherein a hollow shaft M is journalled in a suitable frame member 11 by a bearing 12. Grooves are formed in'shaft 1% adjacent opposite sides of the bearing to receive O-rings i3 and 14, thereby preventing axial movement of the bearing on the shaft. A drive gear 15 is mounted on the drive shaft 16 which is adapted to be driven by a suitable motor (not shown), gear 15 being arranged to mesh with a gear 17 which is fixed to shaft 10 by any suitable means. 7

At the end of shaft 10 opposite the end upon which gear 17 is mounted there is provided a flange illustrated by reference numeral 18. A disc 19 is journalled for rotation on shaft 10 between flange l8 and O-ring 1?). Near the outer peripheral edge of disc 19 there is provided a pawl 20 which is pivotally mounted on the disc by a suitable pin 21. One end of the pawl is provided with a tooth ZZWhiCh is adapted at certain timesto enter a detent 23 in flange 1'8. i

The output shaft, illustrated by reference numeral 24, is rotatably journalled in the hollow shaft it said output shaft having a reduced portion 25 at one end thereof. A flange 26 is formed on shaft 24 adjacent said reduced portion for abutting relation with one end of the hollow shaft iii. A groove is formed in shaft 24 adjacent the other end of the hollow shaft so as to receive an O-ring 27. Flange 26 and O-ring 27 serve to prevent axial move ment of the shaft 24- in the hollow shaft.

A spiral spring has one end fixed to the reduced portion 25 of the output shaft and the other end connected to a pin 29 projecting from one end of pawl 20.

'Pawl '20 has two positions respectively illustrated in FIGS. 1 and 2; As shown in FIG. 1, spring 2% is surficiently unwound so that the end thereof connected to pawl 20 urges the pawl to rotate in a clockwise direction about pin 21 until the tooth 22 engages the detent 23 in flange 18. With flange 18 being continuously rotated in a counter clockwise direction, disc 19 will also be rotated in the same direction, thereby causing the spring 28 to be wound. As the spring winds up, the overall diameter of the spring decreases. As this occurs, the end of the spring connected to the pawl urges the pawl to pivot in a counter clockwise direction about pin 21 until tooth 22 is disengaged from detent 23. At this time, the spring is completely wound. The energy stored in the wound spring may be released to the output shaft at intervas determined by the load 32 controlling the use of the output shaft. For example, the output shaft could be controlled by an escapement mechanism which would allow one half revolution of the shaft each time it is operated. The escapement mechanism could be operated at fixed intervals or at variable intervals.

An arm 30 pivotally connected to the frame it by pivot pin 31 is urged against the periphery of the disc 19 by a spring 32 so as to prevent the disc from rotating in a clock wise direction. It will be seen that this is necessary, for without the arm or its equivalent, the spring could not remain wound.

As soon as the output shaft is rotated suficientiy to allow the end of the spring connected to the pawl to cause the pawl to rotate in a clockwise direction to a point where tooth 22 engages detent 23, the winding operation begins again. The speed of rotation of the hollow shaft it and the size of spring 2% are chosen such that the output shaft will have a relatively constant torque available at all times. That is, by the time the output shaft has rotated sufficiently to unwind the spring to the point where its torque begins to decrease, the pawl will engage the detent and the spring will be rewound. In most applications, it is possible to obtain a larger number of revolutions over a short period of time from the output shaft that the number of revolutions the input shaft is rotating during the same time. This is advantageous in allowing the size of the drive motor to be reduced since the relatively short periods of use of the output shaft at a high rate of revolutions are sufiiciently spaced in time to allow torque to always be available.

From the above, it will be seen that I have provided a new and improved spring drive or spring motor for furnishing a substantially constant torque to an output shaft. The output shaft may be used intermittently or at varying rates for varying intervals of time and the spring is capable of indicating when rewinding is necessary. As mentioned heretofore, the output shaft may rotate at a higher number of revolutions per minute for a short period of time than the rotation in revolutions per minute of the drive motor. The device affords a simple means for automatically winding the spring when it is necessary to rewind it, even though the rewinding intervals are variable.

While there have been shown and described and pointed out the fundamental novel features of the invention as applied to a preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art, without departing from the spirit of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the following claims.

What is claimed is:

1. Spring drive apparatus comprising frame means having a continuously running input shaft and an output shaft journalled therein for independent relative rotation, a storage spring having one end thereof connected to said output shaft, rotatable means journalled for rotation on said input shaft, pawl means, means for pivotally mount ing said pawl means on said rotatable means, the other end of said storage spring being connected to said pawl means on one side of the pivotal mounting means, said pawl means having means on the other side of said pivotal mounting means for engaging said continuously running input shaft when said storage spring is unwound to a predetermined degree so that said rotatable means is caused to rotate with said input shaft and wind said storage spring, said rotatable means being decoupled from said input shaft when said spring is wound to a predetermined degree.

2. Spring drive apparatus comprising a frame member, a continuously running hollow shaft journalled in said frame member, rotatable means journalled on said hollow shaft, means for preventing said rotatable means from rotating in a direction opposite the direction of rotation of said hollow shaft, a pawl pivotally connected intermediate the ends thereof to said rotatable means,

said pawl having a tooth on one end thereof adapted to engage said hollow shaft, an output shaft journalled in said hollow shaft, and a spiral storage spring having one end connected to said output shaft and the other end connected to the other end of said pawl, the unwound condition of said storage spring urging said pawl to pivot in one direction until said tooth engages said hollow shaft so that the rotatable means is caused to rotate with said hollow shaft until said spring is wound to a degree whereby the spring urges said pawl to pivot in the opposite direction until it is disengaged from said hollow shaft.

3. Spring drive apparatus comprising a frame member, a continuously running input shaft and an output shaft journalled on said frame member, a rotatable member journalled on said input shaft, means engaging said rotatable member for allowing rotation in a single direction, an elongated pawl pivotally connected intermediate the ends thereof to said rotatable member, said pawl having a tooth on one end thereof, said input shaft having a detent therein adapted to be engaged by the tooth on said pawl, and a spiral storage spring having one end connected to said output shaft and the other end connected to the other end of said pawl, the arrangement being such that when said spring has reached a predetermined unwound state it urges the pawl to rotate about its pivot until the tooth therein engages the detent and said continuously running input shaft so as to clutch said rotatable member to said input shaft for rotation therewith so as to wind said storage spring, the arrangement being further that when said storage spring has reached a predetermined wound state it urges said pawl to rotate about its pivot until the tooth thereon is disengaged from said input shaft.

References Cited in the file of this patent UNITED STATES PATENTS 424,418 Hitt Mar. 25, 1890 884,961 Sylvan Apr. 14, 1908 1,332,870 Gill Mar. 2, 1920 1,458,333 Gill June 12, 1923 1,978,973 Whitehead et al. Oct. 30, 1934 UNITED STATES PATENT OFFICE CERTIFICATION OF CORRECTION Patent Noo 3 Ol4 555 December 26 1961 Richard CD Lord It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2 line 52 for "intervals" read intervals --=5 column 3 line 5 for "that" read than Signed and sealed this 24th day of April 1962;

(SEAL) Attest:-

ESTON G1a JOHNSON DAVID L, LA. Attesting Officer Commissioner of Patents 

